A new method was developed to evaluate air quality by considering changes in pollutant levels. By analyzing data from 10 cities in Shaanxi Province, researchers found that different cities had varying trends in air quality improvement. Central cities showed potential for improvement in PM2.5 and O3 levels, while PM2.5 remained a key factor in winter air quality. O3 pollution in summer was not effectively controlled, leading to worsened air quality. Coordinated efforts to control both PM2.5 and O3 are crucial for improving ambient air quality.